Once the plan had been decided upon, every available man seems to have been set at work to aid in its speedy execution. Mahomet himself superintended the construction of the new fortification and pushed on the works with the energy that characterised all his military undertakings. At the beginning of the operations Constantine with the object of saving the crops of the peasants around the city, and of appearing to be reconciled to the project which he could not prevent, sent provisions to the workmen. Mahomet in reply, and probably with the intention of forcing on war in the open, permitted his men to scour the country and gather or destroy the crops. All the neighbouring churches and houses, including the famous church of the Asomatoi at Arnoutkeui, were destroyed to furnish material.[205] The land enclosed, says Critobulus, was rather a fortified town than a fort. The walls and towers still remain and form the most picturesque object which the traveller sees on his passage through the Bosporus. Each of two peaks is crowned with a strong tower. These are connected by a long high wall interrupted with smaller towers, and from the two largest towers similar walls at right angles to the long wall connect them with great towers on the shore at the end of another line of walls parallel to the channel. Small guns or bombards enabled the enclosure to be defended against any attack by land. On the sea shore and under the protection of the walls were stationed large cannon which threw heavy stone balls and commanded the passage. [Sidenote: Completed middle of August 1452.] [Sidenote: War declared.] The work had been commenced in March 1452. It was completed by the middle of August of the same year. The city had hoped to maintain peace and Turks had entered and left it apparently without difficulty. When the fortification was finished and Mahomet’s army had robbed the peasants of their crops, this hope vanished. Constantine closed the gates, making the few Turks within its walls prisoners. They were, however, a few days afterwards sent to the sultan. Upon the closing of the gates, Mahomet formally declared war and followed up his declaration by appearing with an army of fifty thousand men before the walls. But his preparations for a siege were far from ready. After remaining three days he withdrew on September 6 to Adrianople and at the same time the fleet returned to the Dardanelles.[206] [Sidenote: Capture of ships at Roumelia-Hissar.]